In the prior art, applicant is aware of numerous devices and methods for exterminating burrowing animals such as gophers, moles and also various insects including fire ants wherein extermination is accomplished by, for example, suffocation by a gas which is injected in a toxic amount to reportedly cause respiratory failure, pulmonary oedema, coma and/or death, carbon monoxide when exhausted from an internal combustion engine, or poisoning by the use of for example anhydrous ammonia in a liquid state, or chlorine or other rodenticides, or by heat and/or concussive explosion by the injection of combustibles into the burrows followed by subsequent ignition, or by the use of underground netting so as to entangle and thereby trap the burrowing animal, and of course the use of more conventional above ground traps.
As reported by Kleisath in his U.S. Pat. No. 5,548,921 which issued Aug. 27, 1996 for his Method and Apparatus for Gassing Gophers, in various localities gophers have become unwanted pests due to uncontrollable damage to orchards, gardens and other types of vegetation. Gophers or moles live in underground burrows which may include individual tunnels or runs of one-half mile or more in length. A community of gophers typically build a labyrinth of such underground runs and can become severe economic liabilities to farmers and other people engaged with agriculture. Accordingly, many measures have been taken by farmers and gardeners to eradicate these animals. Unfortunately, the extent of the underground labyrinth of tunnels and the multiple exits from these tunnels have made gophers extremely difficult to find and kill.
According to Kleisath one known method of killing gophers or moles is to introduce a poisonous gas through one of the entrance or exit holes into the gopher burrow. The gas either kills the gopher or drives the gopher out through another hole where it can be killed by conventional means, e.g. a gun or club. Kleisath notes that it is important to ensure that the poisonous gas does not escape back through the entrance hole, thereby causing damage to surrounding agriculture or possibly being inhaled by the user. According to Kleisath, to prevent this from occurring, the prior art has mainly focused on pressurized cartridges that form poisonous gases, such as chloro-cyanic gas, through chemical combustion and then distribute these pressurized gases into the gopher burrows.
Kleisath discloses forming a shallow hole in the ground with a tip of a probe to locate the gopher burrow. A shallow hole is formed in the ground with the tip of the probe to locate the gopher burrow. A dry solid chlorine material is introduced into the burrow and water is poured into the hole onto the dry chlorine material to generate chlorine gas. The hole is then closed to seal the gaseous poison within the burrow, thereby allowing the gaseous poison to expand throughout the burrow and gas the animal.